The present invention relates generally to hydraulic cylinder units and more particularly to a device for tripping the poppet of a hydraulic cylinder unit piston to enable synchronization.
It has become desirable in various industries to have hydraulic cylinders that move in synchronization with each other, whether it be a retracting motion or an extending motion or both. Such a set of cylinders are referred to as series cylinders.
To insure that the set of cylinders do not get out of synchronization due to volume differentials inherent within the cylinders, a means to bypass fluid around the piston at the end of either the retracting and/or extending motion must be incorporated into the hydraulic cylinders.
A known type of series cylinder in the prior art includes a poppet in the piston rod, the poppet being tripped when it strikes the end of the cylinder butt plate. But this means for bypassing fluid across the piston is expensive to manufacture and difficult to assemble and maintain.
Another problem associated with series cylinders of the prior art is that they have generally been highly susceptible to contamination. This is because the poppet seat mechanisms have been formed of a relatively soft material so that the high velocity fluid passing through the poppet tends to embed foreign matter into the valve seats.
These and other problems of the prior art are believed to be resolved by the poppet trip device of the present invention.
Accordingly, a primary object of the present invention is to provide an improved series cylinder.
Another object is to provide a series cylinder including a movable poppet installed within the piston thereof.
A further object is to provide such a series cylinder including means for tripping or unseating the poppet at both ends of the hydraulic cylinder unit.
A further object is to provide such a series cylinder including means for enabling a piston mounted poppet to indirectly contact the base end of the cylinder for tripping the poppet.
Another object is to provide an hydraulic cylinder poppet trip device which is easy and economical to manufacture and easy to assemble and maintain.
A further object is to provide a series cylinder poppet trip device which has little or no susceptibility to contamination.